CR+LF?

I heard that internet mails must use CR+LF and not LF.
If it is true, what happens to my mails created in recipe
which seems to be using LFs since it is in UNIX world.

Are LFs automatically converted to CR+LFs by sendmail?
Or it does not really matter?
Or?

I hope you understand what I mean:-)
_/_/_/      Mitsuru FURUKAWA      _/_/_/
_/_/_/        Tokyo, Japan        _/_/_/
_/_/_/     mailto:furu(_at_)009(_dot_)com    _/_/_/
_/_/_/  http://www.009.com/furu/  _/_/_/